Experimental Studies of Mimicry in Some North American Butterflies: Part I. The Monarch, Danaus plexippus, and Viceroy, Limenitis archippus archippus

Evolution ◽  
1958 ◽  
Vol 12 (1) ◽  
pp. 32 ◽  
Author(s):  
Jane van Zandt Brower

Author(s):  
Felipe Dargent ◽  
Sydney M Gilmour ◽  
Emma A Brown ◽  
Rees Kassen ◽  
Heather M Kharouba

Every year monarch butterflies (Danaus plexippus Linnaeus, 1758) from the eastern North American population migrate from Mexico to Southern Canada in the spring. This northward migration has been shown to reduce monarch infection with the host-specific parasite Ophryocystis elektroscirrha (OE) (McLaughlin and Myers, 1970); yet, the prevalence of OE at their range limits, and the mechanism(s) responsible, is unknown. We assessed OE infection levels of monarchs at the northern edge of the eastern population distribution around Ottawa, Canada, and found extremely low levels of infection (~1% with upper confidence intervals close to 3%). Low OE infection levels are likely due to low densities of monarchs in this region and/or migratory escape effects, where migrating individuals leave behind areas with high density of conspecifics and high potential for parasite accumulation and transmission. Future work should aim to disentangle the relative contribution of these two mechanisms for governing the decrease in parasitism at the range limits of migratory populations.



2008 ◽  
Vol 57 (4) ◽  
pp. 270-275 ◽  
Author(s):  
Cristina Lasaitis ◽  
Rafaela Larsen Ribeiro ◽  
Orlando Francisco Amodeo Bueno

OBJECTIVE: The study presents the Brazilian norms for 240 new stimuli from International Affective Picture System (IAPS), a database of affective images widely used in research, compared to the North-American normative ratings. METHODS: The participants were 448 Brazilian university students from several courses (269 women and 179 men) with mean age of 24.2 (SD = 7.8), that evaluated the IAPS pictures in the valence, arousal and dominance dimensions by the Self-Assessment Manikin (SAM) scales. Data were compared across the populations by Pearson linear correlation and Student's t-tests. RESULTS: Correlations were highly significant for all dimensions; however, Brazilians' averages for arousal were higher than North-Americans'. CONCLUSIONS: The results show stability in relation to the first part of the Brazilian standardization and they are also consistent with the North-American standards, despite minor differences relating to interpretation of the arousal dimension, demonstrating that IAPS is a reliable instrument for experimental studies in the Brazilian population.



2020 ◽  
Author(s):  
Alana A. E. Wilcox ◽  
Amy E. M. Newman ◽  
Nigel E. Raine ◽  
D. Ryan Norris

AbstractEastern North American migratory monarch butterflies (Danaus plexippus) have faced sharp declines over the last two decades. Although captive rearing has been used as an important tool for engaging the public and supplementing conservation efforts, a recent study that tested monarchs in a flight simulator suggested that captive-reared monarchs lose their capacity to orient southward during fall migration to their Mexican overwintering sites. We raised offspring of wild-caught monarchs on swamp milkweed (Asclepias incarnata) and, after eclosion, individuals were either tested in a flight simulator or radio-tracked in the wild using array of over 100 automated telemetry towers. While only 33% (7/39) of monarchs tested in the flight simulator showed strong southeast to southwest orientation, 97% (28/29) of the radio-tracked individuals were detected by automated towers south or southeast of the release site, up to 200 km away. Our results suggest that, though captive rearing of monarch butterflies may cause temporary disorientation, proper orientation is likely re-established after exposure to natural skylight cues.



2021 ◽  
Author(s):  
Lauren Petrullo ◽  
Tiantian Ren ◽  
Martin Wu ◽  
Rudy Boonstra ◽  
Rupert Palme ◽  
...  

Gut microbiome diversity plays an important role in host health and fitness, in part through the diversification of gut metabolic function and pathogen protection. Elevations in glucocorticoids (GCs) appear to reduce gut microbiome diversity in experimental studies, suggesting that a loss of microbial diversity may be a negative consequence of increased GCs. However, given that ecological factors like food availability and population density may independently influence both GCs and microbial diversity, understanding how these factors structure the GC-microbiome relationship is crucial to interpreting its significance in wild populations. Here, we used an ecological framework to investigate the relationship between GCs and gut microbiome diversity in wild North American red squirrels (Tamiasciurus hudsonicus). We found that higher GCs predicted lower gut microbiome diversity and an increase in metabolic taxa. In addition, we identified a loss of potentially pathogenic bacteria with increasing GCs. Both dietary heterogeneity and an upcoming masting event exhibited direct effects on gut microbiome diversity, whereas conspecific density and host reproductive activity impacted diversity indirectly via changes in GCs. Together, our results suggest that GCs coordinate the effects of ecological change and host biology on gut microbiome diversity, and highlight the importance of situating the GC-microbiome relationship within an ecological framework.



2019 ◽  
Vol 8 (1) ◽  
pp. 22 ◽  
Author(s):  
Hailey Wilmer ◽  
Lauren Porensky ◽  
María Fernández-Giménez ◽  
Justin Derner ◽  
David Augustine ◽  
...  

In the North American Great Plains, multigenerational ranches and grassland biodiversity are threatened by dynamic and uncertain climatic, economic, and land use processes. Working apart, agricultural and conservation communities face doubtful prospects of reaching their individual goals of sustainability. Rangeland research could serve a convening platform, but experimental studies seldom involve local manager communities. The Collaborative Adaptive Rangeland Management (CARM) project, however, has undertaken a ten-year, ranch-level, participatory research effort to explore how community-engaged research can increase our understanding of conservation and ranching goals. Using ethnographic data and the nature-culture concept—which recognizes the inseparability of ecological relationships that are shaped by both biological and social processes—we examine the CARM team’s process of revising their management objectives (2016–2018). In CARM’s early days, the team established locally-relevant multifunctional goals and objectives. As team members’ understanding of the ecosystem improved, they revised objectives using more spatially, temporally and ecologically specific information. During the revision process, they challenged conventional ecological theories and grappled with barriers to success outside of their control. The emerging CARM nature-culture, based on a sense of place and grounded in hope, provides insights into effective community-engaged research to enhance rangeland livelihood and conservation outcomes.



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